Antenna, sensor, and in-vehicle system

ABSTRACT

Provided is an antenna which includes a plurality of radiating portions which are formed on a substrate and a plurality of dielectric lenses for respectively converting a spherical wave radiated from each radiating portion into a plane wave, wherein the shape of a cross section of each dielectric lens perpendicular to a radiation direction of a beam is formed in a shape which radiates a beam which is narrower in a second direction than in a first direction orthogonal to the second direction, and the plurality of dielectric lenses are arranged side by side in the second direction so that beams radiated from the respective dielectric lenses are synthesized.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority fromJapanese Patent Application No. 2016-103958, filed May 25, 2016, theentire contents of which are incorporated herein reference.

TECHNICAL FIELD

The present invention relates to an antenna for generating a flat beam.

BACKGROUND ART

There are Doppler sensors or radars using radio waves as surroundingsituation detection sensors for safe navigation and safe operation ofautomobiles, railways, infrastructure equipment and the likes. For thesake of simplifying below description, a Doppler sensor for automobileswill be described.

For automobiles, a plurality of sensors covering all areas around theautomobile, such as forward long distance, forward middle distance,forward short distance, sideward, rearward middle distance, and thelike, are used for safe driving support and automatic driving. For thisreason, it is possible to detect various target objects such as forwardobstacles, preceding vehicles, rear vehicles, people, and the likes,according to a driving scene.

As background arts of the technology, there are JP-A-2012-52928 (PTL 1),JP-A-2012-222507 (PTL 2), JP-A-2000-228608 (PTL 3), and JP-A-1998-160838(PTL 4).

JP-A-2012-52928 (PTL 1) discloses an antenna which generates a flat beamby setting a parallel number of antenna elements such that differentnumbers are set between a direction connected to a feed line and adirection not connected. JP-A-2012-222507 (PTL 2) discloses an antennafor generating the flat beam by setting the parallel number oftransmitting-side unit antennas and receiving-side unit antennas suchthat different numbers are set between a horizontal direction and avertical direction.

However, with the antennas disclosed in JP-A-2012-52928 (PTL 1) andJP-A-2012-222507 (PTL 2), there is a problem in that the feed line forsupplying electric power to the antenna element or the unit antennabecomes long, and thus an antenna gain decreases due to loss of the feedline.

JP-A-2000-228608 (PTL 3) discloses an antenna which is constituted of aprimary radiator constituted of a dielectric lens, a patch antenna, anda metallic horn and in which the primary radiator is disposed at a focalposition of the dielectric lens. JP-A-1998-160838 (PTL 4) discloses anantenna which converges electromagnetic waves radiated from a powersupply portion with the dielectric lens. In the antennas disclosed inJP-A-2000-228608 (PTL 3) and JP-A-1998-160838 (PTL 4), electromagneticwaves are collected by the dielectric lens or the horn to improve theantenna gain.

SUMMARY OF INVENTION Technical Problem

In such a sensor, a beam shape of an electromagnetic wave transmitted orreceived from an antenna needs to be a flat shape which is wide in ahorizontal direction and narrow in a vertical direction. The reason forthis is that it is desirable to widen a viewing angle with respect to atarget object in the horizontal direction, and noise (load clutternoise) due to unnecessary radiation from the ground is reduced in thevertical direction, in such a manner that the detection sensitivity ofthe received signal is increased and thus distant obstacles aredetected.

When the structure disclosed in JP-A-2000-228608 (PTL 3) is adopted inorder to reduce the loss due to the feed line as in JP-A-2012-52928(PTL 1) and JP-A-2012-222507 (PTL 2), the primary radiator is disposedat a position separated from the dielectric lens by the focal length,and the focal length is sufficiently longer than the wavelength of theelectromagnetic wave. Therefore, the electromagnetic waves radiated fromthe primary radiator are distributed on a substantially circular shapeon an opening surface of the dielectric lens, and the electromagneticwaves radiated from the dielectric lens have a substantially isotropicbeam shape. Thus, there is a problem in that a flat beam cannot begenerated.

In the antennas disclosed in JP-A-2000-228608 (PTL 3) andJP-A-1998-160838 (PTL 4), electromagnetic waves radiated from theprimary radiator and the power supply portion are collected by onedielectric lens. Therefore, there is a problem in that the focal lengthof the dielectric lens becomes long and the size of the antenna becomeslarge.

For this reason, a compact antenna for generating a flat beam isrequired.

Solution to Problem

A representative example of the invention disclosed in the applicationis as follows. That is, there is provided an antenna which includes aplurality of radiating portions which are formed on a substrate and aplurality of dielectric lenses for respectively converting a sphericalwave radiated from each radiating portion into a plane wave, wherein theshape of a cross section of each dielectric lens perpendicular to aradiation direction of a beam is formed in a shape which radiates a beamwhich is narrower in a second direction than in a first directionorthogonal to the second direction and the plurality of dielectriclenses are arranged side by side in the second direction so that beamsradiated from the respective dielectric lenses are synthesized.

Advantageous Effects of Invention

According to an aspect of the invention, it is possible to reduce thesize of an antenna for generating a flat beam. Problems, configurations,and effects other than those described above will be clarified by thedescription of the following examples.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a structural diagram of a flat beam generating antennaaccording to an example of the invention.

FIG. 2A is a structural diagram of a flat beam generating antennaaccording to an example of the invention.

FIG. 2B is a structural diagram of a flat beam generating antennaaccording to an example of the invention.

FIG. 2C is a structural diagram of a flat beam generating antennaaccording to an example of the invention.

FIG. 3A is a structural diagram of a flat beam generating antennaaccording to an example of the invention.

FIG. 3B is a structural diagram of a flat beam generating antennaaccording to an example of the invention.

FIG. 4 is a structural diagram of a flat beam generating antennaaccording to an example of the invention.

FIG. 5 is a structural diagram of a flat beam generating antennaaccording to an example of the invention.

FIG. 6 is a block diagram of a transmitting side of a sensor including aflat beam generating antenna according to an example of the invention.

FIG. 7 is a block diagram of a transmitting side of a sensor including aflat beam generating antenna according to an example of the invention.

FIG. 8 is a block diagram of a receiving side of a sensor including aflat beam generating antenna according to an example of the invention.

FIG. 9 is a block diagram of a sensor including a flat beam generatingantenna according to an example of the invention.

FIG. 10 is a structural diagram of a sensor including a flat beamgenerating antenna according to an example of the invention.

FIG. 11A is a block diagram of a sensor including a flat beam generatingantenna according to an example of the invention.

FIG. 11B is a block diagram of a sensor including a flat beam generatingantenna according to an example of the invention.

FIG. 11C is a block diagram of a sensor including a flat beam generatingantenna according to an example of the invention.

FIG. 12 is a block diagram of a sensor including a flat beam generatingantenna according to an example of the invention.

FIG. 13 is a block diagram of an in-vehicle system including a sensorincluding a flat beam generating antenna according to an example of theinvention.

FIG. 14 is a view illustrating an attachment angle of a flat beamgenerating array antenna according to an example of the invention.

FIG. 15 is a view illustrating an attachment angle of the flat beamgenerating array antenna according to an example of the invention.

DESCRIPTION OF EMBODIMENTS

Hereinafter, the best mode for carrying out the invention will bedescribed in detail with reference to drawings. In the drawings forexplaining the best mode for carrying out the invention, the samereference numerals and characters are given to members having the samefunction and the repetitive description thereof will be omitted.

Example 1

FIGS. 1 and 2A are structural diagrams of a flat beam generating arrayantenna according to an example of the invention.

In the antenna illustrated in FIGS. 1 and 2A, a first radiating portion110 a and a second radiating portion 110 b are formed on a first surfaceof a dielectric substrate 100. A first conductor portion 120 a is formedon the first surface of the dielectric substrate 100 and a secondconductor portion 130 a is formed on a second surface opposite to thefirst surface of the dielectric substrate 100. In addition, a throughhole 400 a is formed for electrically connecting the conductor on thefirst surface of the dielectric substrate 100 and the conductor on thesecond surface. First horns 200 a, at least inner surfaces of which areformed of the conductor, is attached on the first face side of thedielectric substrate 100, and a first dielectric lens 300 a is disposedin the vicinity of a radiation-side opening portion of each first horn200 a. With such a configuration, the antenna of Example 1 radiatesradio waves substantially in parallel with a first optical axis D1 a-D1a′ and a second optical axis D1 b-D1 b′ of the first dielectric lenses300 a.

A first imaginary line (longitudinal center line) A1-A1′ is a linepassing through centers of the radiation-side opening portions of thefirst horns 200 a in the shortest length. A second imaginary line(transverse center line) B1-B1′ is a line passing through the center ofthe first imaginary line A1-A1′ and perpendicular to the first imaginaryline A1-A1′.

In the antenna of the example, one half of the first imaginary lineA1-A1′ (that is, the length of one radiation-side opening portion in theA1-A1′ direction) is longer than the second imaginary line B1-B1′. Thatis, in the example, the radiation-side opening portion of the first horn200 a has a rectangular shape in which a direction (longitudinaldirection) of the first imaginary line A1-A1′ is longer than a directionof the second imaginary line B1-B1′ (transverse direction).

A third imaginary line C1-C1′ is a line passing through the intersectionof the first imaginary line A1-A1′ and the second optical axis D1 b-D1b′ and perpendicular to the first imaginary line A1-A1′.

(A) of FIG. 1 illustrates a shape of the antenna of the example as seenfrom a radiation-side opening portion side of the first horn 200 a. (B)of FIG. 1 illustrates a cross-sectional shape of the antenna of theexample along the first imaginary line A1-A1′. (C) of FIG. 1 illustratesa cross-sectional shape of the antenna of the example along the thirdimaginary line C1-C1′.

FIG. 2A illustrates a shape of the dielectric substrate 100 as seen froma first surface side.

On the first surface of the dielectric substrate 100, the firstconductor portion 120 a is formed to surround the first radiatingportion 110 a and the second radiating portion 110 b leaving a certaindistance from the first radiating portion 110 a and the second radiatingportion 110 b. The first conductor portion 120 a is electricallyconnected to the second conductor portion 130 a formed on the secondsurface of the dielectric substrate 100 via the through hole 400 a. As aresult, the first conductor portion 120 a and the second conductorportion 130 a function as reference potential planes of the firstradiating portion 110 a and the second radiating portion 110 b and eachof the first radiating portion 110 a and the second radiating portion110 b operates as a patch antenna, and thus an electromagnetic wave isradiated from the first surface side of the dielectric substrate 100.

Furthermore, radiation-source-side opening portions which are positionedon a side opposite to the radiation-side opening portions of the firsthorns 200 a in a radio wave travelling direction are disposed on thefirst surface side of the dielectric substrate 100 so as to involve thefirst radiating portion 110 a and the second radiating portion 110 brespectively. That is, the first horns 200 a have two left-rightsymmetric horn shapes symmetrical with the second imaginary line B1-B1′as an axis.

As described above, the antenna of the example is constituted of thefirst radiating portion 110 a, the second radiating portion 110 b, andtwo first horns 200 a.

It is preferable that the interval at which the through holes 400 a arearranged be set to be shorter than the length of a quarter of thewavelength of an electromagnetic wave to be used within the dielectricsubstrate 100.

Further, the potential of the first horn 200 a can be made equal to thereference potential of the first radiating portion 110 a and the secondradiating portion 110 b by electrically connecting the first horn 200 ato the first conductor portion 120 a, and thus the electromagnetic wavesradiated from the first radiating portion 110 a and the second radiatingportion 110 b can be efficiently transmitted to the first horns 200 a.

Furthermore, the first dielectric lens 300 a having a convex shape inthe direction of the radiation-source-side opening portion is arrangedin the radiation-side opening portion of the first horn 200 a, in such amanner that the length of the first horn 200 a from theradiation-source-side opening portion to the radiation-side openingportion can be shortened, and thus the size of the antenna can bereduced. Further, first dielectric lenses are formed in consecutiveconvex shapes in the direction of the first imaginary line A1-A1′, thenumber of the consecutive convex shape and the number of the radiatingportions 110 a and 110 b being the same. That is, two first dielectriclenses 300 a of the antenna of the example are consecutively arranged inthe direction of the first imaginary line A1-A1′ and has a left-rightsymmetric convex shape with respect to the second imaginary line B1-B1′as an axis. Further, the first radiating portion 110 a and the secondradiating portion 110 b are arranged at positions approximatelycorresponding to the focal position of the first dielectric lens 300 a.The diameter of the convex shape constituting the first dielectric lens300 a is longer than the dimension of the first horn 200 a in adirection along the third imaginary line C1-C1′ in the plane of theradiation-side opening portion.

According to the structure described above, the diameter of the firstdielectric lens 300 a is shortened to one-half of that of a case wherethe first dielectric lens 300 a has one convex shape. In this case, thediameter of the dielectric lens and the focal length are substantiallyproportional to each other in general, and thus the focal length of thefirst dielectric lens 300 a is shortened to approximately one-half.Therefore, the size thereof can be reduced in the electromagnetic waveradiation direction (direction of the first optical axis D1 a-D1 a′ orthe second optical axis D1 b-D1 b′).

Further, the first dielectric lens 300 a is formed into a cylindricalshape having a hyperbolic shape in the direction of the first imaginaryline A1-A1′ and a linear shape in the direction of the second imaginaryline B1-B1′, in such a manner that side lobes in the direction of thefirst imaginary line A1-A1′ and the direction of the second imaginaryline B1-B1′ of the beam radiated from the first dielectric lens 300 acan be reduced.

Further, it is preferable that, in the direction of the first imaginaryline A1-A1′, the center of the first radiating portion 110 a is locatedat the intersection of the first optical axis D1 a-D1 a′ of the firstdielectric lens 300 a and the first surface of the dielectric substrate100, and the center of the second radiating portion 110 b is located atthe intersection of the second optical axis D1 b-D1 b′ of the firstdielectric lens 300 a and the first surface of the dielectric substrate100.

Next, the operation of the antenna of the example will be described. Thespherical electromagnetic wave radiated from the first radiating portion110 a propagates in the first horn 200 a, is input to the firstdielectric lens 300 a, and propagates in the first dielectric lens 300a, and then the electromagnetic wave is radiated to the space. Duringthe propagation, the first horn 200 a and the first dielectric lens 300a convert the spherical wave into the plane wave. Similarly, a sphericalelectromagnetic wave radiated from the second radiating portion 110 bpropagates in the first horn 200 a and the electromagnetic wave isconverted from the spherical wave to the plane wave by the first horn200 a and the first dielectric lens 300 a during the propagation.

Further, the plane electromagnetic wave originated in the firstradiating portion 110 a and radiated from the first horn 200 a, and theplane electromagnetic wave originated in the second radiating portion110 b and radiated from the first horn 200 a are synthesized in a spaceoutside the radiation-side opening portion of the first horn 200 a andradiated as plane electromagnetic waves.

By such operation, the antenna of the example can radiate a beam havingdirectivity in a desired direction.

Further, the antenna of the example has a structure in which two hornsare in a row in the longitudinal direction, and half (the length of theradiation-side opening portion of one horn in the direction of the firstimaginary line A1-A1′) of the first imaginary line A1-A1′ is longer thanthe second imaginary line B1-B1′. That is, in one dielectric lens 300 a(a part of the dielectric lens corresponding to one radiating portion)provided on the radiation side of the antenna, the length in thedirection of the first imaginary line A1-A1′ is longer than the lengthin the direction of the second imaginary line B1-B1′. In the antenna ofthe example, the first imaginary line A1-A1′ is arranged in thelongitudinal direction and the second imaginary line B1-B1′ is arrangedin the transverse direction. Therefore, regarding the shape of the beamradiated from the first horn 200 a, a flat beam in which the width inthe direction (transverse direction) of the second imaginary line B1-B1′is greater than the width in the direction (longitudinal direction) ofthe first imaginary line A1-A1′ is generated.

It is preferable that the electric field plane direction (B planedirection) of electromagnetic waves radiated from the first radiatingportion 110 a and the second radiating portion 110 b be arranged inparallel to the first imaginary line A1-A1′, in such a manner that theshape of the beam radiated from the first horn 200 a is likely to benarrowed in the first imaginary line A1-A1′ direction.

Example 2

FIGS. 2B and 2C are structural diagrams of a flat beam generating arrayantenna according to an example of the invention and illustrate shapesas viewed from the first surface side of the dielectric substrate 100.Variations of a feed line are illustrated in the second example.

In the antenna illustrated in FIGS. 2B and 2C, the first radiatingportion 110 a is connected to a first feed line 140 a and the secondradiating portion 110 b is connected to the second feed line 140 b. Thefirst conductor portion 120 a is formed to surround the first radiatingportion 110 a and the second radiating portion 110 b leaving a certaindistance from the first radiating portion 110 a and the second radiatingportion 110 b. Also, the first conductor portion 120 a is formed leavinga certain distance from the first feed line 140 a and the second feedline 140 b.

With such a configuration, energy for electromagnetic waves to beradiated is supplied to the first radiating portion 110 a via the firstfeed line 140 a. Similarly, energy for electromagnetic waves to beradiated is supplied to the second radiating portion 110 b via thesecond feed line 140 b. The antenna gain can be improved by a structurewhere the first radiating portion 110 a is connected to the first feedline 140 a and the second radiating portion 110 b is connected to thesecond feed line 140 b.

In the antenna illustrated in FIG. 2B, the first feed line 140 a isconnected to the first radiating portion 110 a from a downward directionand the second feed line 140 b is connected to the second radiatingportion 110 b from an upper direction. On the other hand, in the antennaillustrated in FIG. 2C, the first feed line 140 a is connected to thefirst radiating portion 110 a from the downward direction and the secondfeed line 140 b is connected to the second radiating portion 110 b fromthe downward direction. Therefore, the phases of the signals suppliedfrom the first feed line 140 a and the second feed line 140 b aredifferent in the antenna illustrated in FIG. 2B and in phase in theantenna illustrated in FIG. 2C. In this manner, signals are supplied, insuch a manner that the beam radiated from the radiation-side openingportion of the first horn 200 a through the first dielectric lens 300 acan be synthesized so that the gain is maximized in the front direction(direction perpendicular to the radiation-side opening portion). Themaximum direction of the gain of the radiated beam can be set in anarbitrary direction by controlling the phases of the signals suppliedfrom the first feed line 140 a and the second feed line 140 b.

Example 3

FIGS. 3A, 3B, and 4 are structural diagrams of a flat beam generatingarray antenna according to an example of the invention. FIGS. 3A and 3Billustrate shapes as viewed from the radiation-side opening portion sideof the first horn 200 a. Example 3 is different from the examplesdescribed above in the horn shape.

In the antenna illustrated in FIG. 3A, the shape of the radiation-sideopening portion of the first horn 200 a is formed such that thedirection of the first imaginary line A1-A1′ is longer than thedirection of the third imaginary line C1-C1′ and four corners are formedin a curved shape (rounded-corner rectangle shape).

Further, in the antenna illustrated in FIG. 3B, the shape of theradiation-side opening portion of the first horn 200 a is formed into anelliptical shape in which a long side in the direction of the firstimaginary line A1-A1′ is longer than a short side in the direction ofthe third imaginary line C1-C1′.

The shape of the radiation-side opening portion of the first horn 200 aof the antenna of the invention may be selected from either arectangular shape illustrated in FIG. 1 or a shape including a curvedportion illustrated in FIG. 3A or 3B in accordance with ease ofmanufacturing and a radiation pattern of the flat beam to be generated.Also, in accordance with the radiation pattern of the flat beam to begenerated, it may be in a shape of a horn having a ridge at theradiation-side opening portion or the radiation-source-side openingportion.

In the antenna illustrated in FIG. 4, a side surface shape of a secondhorn 200 b has a curved shape. The other points are the same as those ofthe antennas of the examples described above. Further, the side surfaceshape of the horn of the antenna of the invention may be a shape otherthan a linear shape (FIG. 1) like the first horn 200 a or a curved shape(FIG. 4) like the second horn 200 b (for example, a shape withirregularities). Even when the shape is selected in accordance with theradiation pattern of the flat beam to be generated, the effects of theflat beam generating array antennas of the invention are the same.

Example 4

FIG. 5 is a structural diagram of a flat beam generating array antennaaccording to an example of the invention. The flat beam generating arrayantenna of Example 4 includes an electromagnetic wave shielding portioninstead of a horn.

(A) of FIG. 5 illustrates a shape of the antenna of the example as seenfrom the radiation-side opening portion side. (B) of FIG. 5 illustratesa cross-sectional shape of the antenna of the example along the firstimaginary line A1-A1′. (C) of FIG. 5 illustrates a cross-sectional shapeof the antenna of the example along the third imaginary line C1-C1′.

The antenna illustrated in FIG. 5 includes a first electromagnetic waveshielding portion 210 a and a second electromagnetic wave shieldingportion 210 b. The first electromagnetic wave shielding portion 210 aincludes a first opening portion having the same shape as theradiation-side opening portion of the first horn 200 a and the firstdielectric lens 300 a is arranged in the first opening portion. Thesecond electromagnetic wave shielding portion 210 b is arranged inbetween the first radiating portion 110 a, the second radiating portion110 b, and the first dielectric lens 300 a, in a direction parallel tothe second imaginary line B1-B1′. In the example, the cross-sectionalshape of the second electromagnetic wave shielding portion 210 b in acase of cutting with a plane parallel to the direction of the firstimaginary line A1-A1′ is a triangle. However, other shapes may be used.

Structures other than those described above are the same as those inExamples 1 to 3.

The electromagnetic waves radiated from the first radiating portion 110a and the second radiating portion 110 b are converted from thespherical wave to the plane wave by the first dielectric lens 300 a andradiated from opening surfaces of the first dielectric lenses 300 a on aside opposite to the first radiating portion 110 a and the secondradiating portion 110 b. In the antenna of the example, the radiation ofelectromagnetic waves is limited by the shape of the first openingportion of the first electromagnetic wave shielding portion 210 a. Inother words, the shape of an electromagnetic wave to be radiated, thatis, the beam, is a flat beam of which the width in the direction of thefirst imaginary line A1-A1′ is narrower than the width in the directionof the second imaginary line B1-B1′.

Since a horn is unnecessary for the antenna of the example, thestructure can be simplified and the cost can be reduced.

Also, the electromagnetic waves radiated from the first radiatingportion 110 a pass a path along the first optical axis D1 a-D1 a′ byarranging the second electromagnetic wave shielding portion 210 b asdescribed above and the electromagnetic wave radiated from the secondradiating portion 110 b passes a path along the second optical axis D1b-D1 b′. That is, electromagnetic waves radiated from mutually differentoptical axes are shielded with the second electromagnetic wave shieldingportion 210 b, in such a manner that it is possible to reduce side lobesof electromagnetic waves, that is, beams, radiated through the firstdielectric lens 300 a.

Example 5

FIG. 6 is a block diagram of a transmitting side of a sensor includingthe flat beam generating array antenna according to Examples 1 to 4described above. In Example 5, an example of the transmitting side ofthe sensor including the flat beam generating array antenna will bedescribed.

A sensor illustrated in FIG. 6 includes a flat beam generating arrayantenna 10 and a first transmission circuit 510 a. The firsttransmission circuit 510 a includes a first terminal 511 a connected tothe first radiating portion 110 a and a second terminal 512 a connectedto the second radiating portion 110 b. The phases of the signals outputfrom the first terminal 511 a and the second terminal 512 a aredetermined by a direction of an electric field plane generated in thefirst radiating portion 110 a and the second radiating portion 110 b andmay be differential or same.

Next, the operation of a transmitting unit of the sensor of the examplewill be described. The signal output from the first terminal 511 a ofthe first transmission circuit 510 a is input to the first radiatingportion 110 a and radiated from the first dielectric lens 300 a as anelectromagnetic wave. Similarly, the signal output from the secondterminal 512 a of the first transmission circuit 510 a is input to thesecond radiating portion 110 b and radiated from the first dielectriclens 300 a as an electromagnetic wave.

The transmitting unit of the sensor including the flat beam generatingarray antenna of the example can be applied to a sensor for measuring adistance to an obstacle or the like, and a relative speed of an obstacleor the like.

Example 6

FIG. 7 is a block diagram of a transmitting side of a sensor having theflat beam generating array antenna according to Examples 1 to 4described above. In Example 6, an example of the transmitting side ofthe sensor in which electricity is supplied to the flat beam generatingarray antenna via a distributer will be described.

The sensor illustrated in FIG. 7 includes the flat beam generating arrayantenna 10, a second transmission circuit 510 b, and a first distributer500 a. The second transmission circuit 510 b includes a third outputterminal 513 a for outputting a signal. The first distributer 500 aincludes a first terminal 501 a, a second terminal 502 a, and a thirdterminal 503 a.

The third terminal 503 a of the first distributer 500 a is connected tothe third output terminal 513 a of the second transmission circuit 510b, the first radiating portion 110 a is connected to the first terminal501 a of the first distributer 500 a, and the second radiating portion110 b is connected to the second terminal 502 a of the first distributer500 a. The phases of the signals output from the first terminal 501 aand the second terminal 502 a are determined by the direction of theelectric field plane generated in the first radiating portion 110 a andthe second radiating portion 110 b and may be differential or same.

Next, the operation of a transmitting unit of the sensor of the examplewill be described. The signals output from the third output terminal 513a of the second transmission circuit 510 b are input to the thirdterminal 503 a of the first distributer 500 a, adjusted to the desiredphase and amplitude at the first distributer 500 a, and output from thefirst terminal 501 a and the second terminal 502 a. The signal outputfrom the first terminal 501 a is input to the first radiating portion110 a and radiated from the first dielectric lens 300 a as anelectromagnetic wave. Similarly, the signal output from the secondterminal 502 a is input to the second radiating portion 110 b andradiated from the first dielectric lens 300 a as an electromagneticwave.

The transmitting unit of the sensor including the flat beam generatingarray antenna of the example can be applied to a sensor for measuring adistance to an obstacle or the like, and a relative speed of an obstacleor the like.

Example 7

FIG. 8 is a block diagram of a receiving side of a sensor including theflat beam generating array antenna according to Examples 1 to 4described above. In Example 7, an example of the receiving side of thesensor including the flat beam generating array antenna will bedescribed.

The sensor illustrated in FIG. 8 includes the flat beam generating arrayantenna 10, a first reception circuit 520 a, and a second receptioncircuit 520 b. The first reception circuit 520 a includes a first inputterminal 521 a connected to the first radiating portion 110 a and thesecond reception circuit 520 b includes a second input terminal 521 bconnected to the second radiating portion 110 b.

Next, the operation of a receiving unit of the sensor of the examplewill be described. The electromagnetic wave input to the firstdielectric lens 300 a is converted into an electrical signal at thefirst radiating portion 110 a via the first dielectric lens 300 a, andinput to the first input terminal 521 a of the first reception circuit520 a. https://ejje.weblio.jp/content/Simultaneously+withSimultaneously, the electromagnetic wave input to the first dielectriclens 300 a is converted into an electrical signal at the secondradiating portion 110 b via the first dielectric lens 300 a, and inputto the second input terminal 521 b of the first reception circuit 520 a.

The receiving unit of the sensor including the flat beam generatingarray antenna of the example can be applied to a sensor for measuring adistance to an obstacle or the like, and a relative speed of an obstacleor the like. Further, since the flat beam generating array antenna ofthe invention generates a flat beam of which a beam width in thelongitudinal direction is longer than that in the transverse directionas described above, it can be applied to a sensor which measures avertical position (angle from a horizontal plane) of an obstacle or thelike in a vertical direction (direction of the first imaginary lineA1-A1′ (not illustrated in FIG. 8)).

Example 8

FIG. 9 is a block diagram of a sensor including the flat beam generatingarray antenna according to the Examples 1 to 4 described above. InExample 8, an example of a sensor in which a transmission unit and areceiving unit are connected to the flat beam generating array antennavia a distributer will be described.

The sensor illustrated in FIG. 9 includes the flat beam generating arrayantenna 10, the second transmission circuit 510 b, a third receptioncircuit 520 c, and a second distributer 500 b. The second transmissioncircuit 510 b includes the third output terminal 513 a for outputting asignal. The second distributer 500 b includes a first terminal 501 b, asecond terminal 502 b, a third terminal 503 b, and a fourth terminal 504b. The second distributer 500 b synthesizes the signals input to thefirst terminal 501 b and the second terminal 502 b, and outputs thesignals from the third terminal 503 b. The second distributor 500 bdistributes the signals input to the fourth terminal 504 b, and outputsthe signals from the first terminal 501 b and the second terminal 502 b.

The fourth terminal 504 b of the second distributer 500 b is connectedto the third output terminal 513 a of the second transmission circuit510 b, the third terminal 503 b of the second distributer 500 b isconnected to a third input terminal 521 c of the third reception circuit520 c, the first radiating portion 110 a is connected to the firstterminal 501 b of the second distributer 500 b, and the second radiatingportion 110 b is connected to the second terminal 502 b of the seconddistributer 500 b.

Next, the operation of the transmitting unit and the receiving unit ofthe sensor of the example will be described. The signal output from thethird output terminal 513 a of the second transmission circuit 510 b isinput to the fourth terminal 504 b of the second distributor 500 b andadjusted to the desired phase and amplitude by the second distributor500 b, and then the signal is output from the first terminal 501 b andthe second terminal 502 b. The signal output from the first terminal 501b is input to the first radiating portion 110 a, and radiated from thefirst dielectric lens 300 a as an electromagnetic wave. Similarly, thesignal output from the second terminal 502 b is input to the secondradiating portion 110 b, and radiated from the dielectric lens 300 a asan electromagnetic wave.

Electromagnetic waves radiated from the first dielectric lens 300 a arereflected by an obstacle or the like. The reflected electromagneticwaves are converted into electric signals at the first radiating portion110 a and the second radiating portion 110 b via the first dielectriclenses 300 a. Further, the electric signal received at the firstradiating portion 110 a is input to the first terminal 501 b of thesecond distributor 500 b, and the electric signal received at the secondradiating portion 110 b is input to the second terminal 502 b of thesecond distributer 500 b. The second distributor 500 b adjusts the inputsignal to a desired phase and amplitude, outputs the signal from thethird terminal 503 b, and the second distributer 500 b inputs the signalto the third input terminal 521 c of the third reception circuit 520 c.

The transmitting/receiving unit of the sensor including the flat beamgenerating array antenna of the example can be applied to a sensor formeasuring a distance to an obstacle or the like, and a relative speed ofan obstacle or the like.

Example 9

FIG. 10 is a structural diagram of a sensor including the flat beamgenerating array antenna according to the Example 1 to 4 describedabove. FIGS. 11A to 11C are block diagrams of the sensor of Example 9.In Example 9, an example of a sensor including a transmitting unit, atransmitting antenna, a receiving unit, and a receiving antenna will bedescribed.

(A) of FIG. 10 illustrates a shape of the flat beam generating arrayantenna of Example 9 as seen from the radiation-side opening portionside of the first horn 200 a, (B) of FIG. 10 illustrates across-sectional shape of the flat beam generating antenna of Example 9taken along a sixth imaginary line C2-C2′, (C) of FIG. 10 illustrates across-sectional shape of the flat beam generating antenna of Example 9taken along a first imaginary line A1-A1′, and (D) of FIG. 10illustrates a shape of the dielectric substrate 100 as seen from thefirst surface side.

The first radiating portion 110 a, the second radiating portion 110 b, athird radiating portion 110 c, a fourth radiating portion 110 d, a fifthradiating portion 110 e, and a sixth radiating portion 110 f arearranged on the first surface (surface on which horns 200 a, 200 b, and200 c are arranged) of the dielectric substrate 100. Each of theradiating portions 110 a to 110 f is connected to a semiconductorelement 600 a mounted on the first surface of the dielectric substrate100 via feed lines 140 a to 140 f.

The semiconductor element 600 a includes the first transmission circuit510 a, the first reception circuit 520 a, the second reception circuit520 b, a fourth reception circuit 520 d, and a fifth reception circuit520 e. The semiconductor element 600 a may be disposed in a gap portionbetween the first horn 200 a, the second horn 200 b, and the dielectricsubstrate 100. The semiconductor element 600 a may be mounted on asecond surface of the dielectric substrate 100. Further, two or moresemiconductor elements 600 a may be mounted on one or both of the firstsurface and the second surface of the dielectric substrate 100.

On the first surface of the dielectric substrate 100, the first horn 200a, the second horn 200 b, and the third horn 200 c are installed. Thefirst to third horns 200 a to 200 c may be connected as the same memberor may be integrally formed.

In radiation-side opening portions of the horns 200 a to 200 c,dielectric lenses 300 a to 300 c having a cylindrical shape arerespectively installed. The first to third dielectric lenses 300 a to300 c may be connected as the same member or may be integrally formed.

The first radiating portion 110 a and the second radiating portion 110 bare respectively disposed in each of two radiation-source-side openingportions of the first horns 200 a, and connected to the semiconductorelement 600 a by the first conductor portion 120 a and a secondconductor portion 120 b. The third radiating portion 110 c and thefourth radiating portion 110 d are respectively disposed in each of tworadiation-source-side opening portions of the second horns 200 b, andconnected to the semiconductor element 600 a by a third conductorportion 120 c and a fourth conductor portion 120 d. The fifth radiatingportion 110 d and the sixth radiating portion 110 f are respectivelydisposed in each of two radiation-source-side opening portions of thethird horns 200 c, and connected to the semiconductor element 600 a by afifth conductor portion 120 e and a sixth conductor portion 120 f.

The transmitting-side antenna and the receiving-side antenna may havethe same size and shape. However, it is preferable for the aspect ratioof the receiving-side antenna be set larger.

As illustrated in FIG. 11A, the first transmission circuit 510 aincludes the first terminal 511 a connected to the first radiatingportion 110 a and the second terminal 512 a connected to the secondradiating portion 110 b. The phases of the signals output from the firstterminal 511 a and the second terminal 512 a are determined by thedirection of electric field planes generated in the first radiatingportion 110 a and the second radiating portion 110 b and may bedifferential or same.

As illustrated in FIG. 11B, the first reception circuit 520 a includesthe first input terminal 521 a connected to the third radiating portion110 c and the second reception circuit 520 b includes the second inputterminal 521 b connected to the fourth radiating portion 110 d.

As illustrated in FIG. 11C, the fourth reception circuit 520 d includesa fourth input terminal 521 d connected to the fifth radiating portion110 e and the fifth reception circuit 520 e includes a fifth inputterminal 521 e connected to the sixth radiating portion 110 f.

Next, the operation of the transmitting unit and the receiving unit ofthe sensor of the example will be described. The signal output from thefirst terminal 511 a of the first transmission circuit 510 a is input tothe first radiating portion 110 a and radiated from the first dielectriclens 300 a as an electromagnetic wave. Similarly, the signal output fromthe second terminal 512 a of the first transmission circuit 510 a isinput to the second radiating portion 110 b and radiated from the firstdielectric lens 300 a as an electromagnetic wave.

Electromagnetic waves radiated from the first dielectric lenses 300 aare reflected by an obstacle or the like. The reflected electromagneticwave is converted into an electrical signal at the third radiatingportion 110 c via the second dielectric lens 300 b, and input to thefirst input terminal 521 a of the first reception circuit 520 a.Simultaneously, the electromagnetic wave input to the first dielectriclens 300 a is converted into an electric signal at the fourth radiatingportion 110 d via the second dielectric lens 300 b, and input to thesecond input terminal 521 b of the second reception circuit 520 b.

Further, the reflected electromagnetic wave is converted into anelectric signal at the fifth radiating portion 110 e via the thirddielectric lens 300 c, and input to the fourth input terminal 521 d ofthe fourth reception circuit 520 d. Simultaneously, the electromagneticwave input to the third dielectric lens 300 c is converted into anelectric signal at the sixth radiating portion 110 f via the thirddielectric lens 300 c, and input to the fifth input terminal 521 e ofthe fifth reception circuit 520 e.

The transmitting/receiving unit of the sensor including the flat beamgenerating array antenna of the example can be applied to a sensor formeasuring a distance to an obstacle or the like, and a relative speed ofan obstacle or the like. Further, in the flat beam generating arrayantenna of the invention, a plurality of radiation-side opening portionsare arranged side by side in an up-down direction and a right-leftdirection, and thus it can be applied to a sensor which measures anup-down position (angle from a horizontal plane) of an obstacle or thelike in the up-down direction (direction of the first imaginary lineA1-A1′) and a right-left position (angle from the front direction) of anobstacle or the like in the right-left direction (direction of the sixthimaginary line C2-C2′).

Example 10

FIG. 12 is a block diagram of another example of a sensor including theflat beam generating array antenna according to Example 9. In Example10, an example of a sensor including a signal processing circuit 700will be described.

The signal processing circuit 700 is connected to the first transmissioncircuit 510 a, the first reception circuit 520 a, the second receptioncircuit 520 b, the fourth reception circuit 520 d, and the fifthreception circuit 520 e. The signal processing circuit 700 supplies asignal to be transmitted from the antenna to the first transmissioncircuit 510 a, and processes the signals output from the first receptioncircuit 520 a, the second reception circuit 520 b, the fourth receptioncircuit 520 d, and the fifth reception circuit 520 e.

Next, the operation of the transmitting unit and the receiving unit ofthe sensor of the example will be described. A first transmission signaloutput from the signal processing circuit 700 and input to the firsttransmission circuit 510 a is output from the first terminal 511 a ofthe first transmission circuit 510 a as the second transmission signal,and further input to the first radiating portion 110 a and radiated fromthe first dielectric lens 300 a as a transmission electromagnetic wave.Similarly, the second transmission signal output from the secondterminal 512 a of the first transmission circuit 510 a is input to thesecond radiating portion 110 b and radiated from the first dielectriclens 300 a as a transmission electromagnetic wave.

Transmission electromagnetic waves radiated from the first dielectriclens 300 a are reflected by an obstacle or the like. The reflectedelectromagnetic wave is converted into a first reception signal at thethird radiating portion 110 c via a second dielectric lens 300 b, andfurther it is input to the first input terminal 521 a of the firstreception circuit 520 a. The first reception signal is output from thefirst reception circuit 520 a as the fifth reception signal and input tothe signal processing circuit 700.

Simultaneously, the reflected electromagnetic wave is converted into thesecond reception signal at the fourth radiating portion 110 d via thesecond dielectric lens 300 b, and further it is input to the secondinput terminal 521 b of the second reception circuit 520 b. The secondreception signal is output from the second reception circuit 520 b as asixth reception signal and input to the signal processing circuit 700.

Simultaneously, the reflected electromagnetic wave is converted into athird reception signal at the fifth radiating portion 110 e via thethird dielectric lens 300 c, and further it is input to the fourth inputterminal 521 d of the fourth reception circuit 520 d. The thirdreception signal is output from the fourth reception circuit 520 d as aseventh reception signal and input to the signal processing circuit 700.

Simultaneously, the reflected electromagnetic wave is converted into afourth reception signal at the sixth radiating portion 110 f via thethird dielectric lens 300 c, and further it is input to the fifth inputterminal 521 e of the fifth reception circuit 520 e. The fourthreception signal is output from the fifth reception circuit 520 e as theeighth reception signal and input to the signal processing circuit 700.

The signal processing circuit 700 combines and processes the signalsoutput from the first reception circuit 520 a, the second receptioncircuit 520 b, the fourth reception circuit 520 d, and the fifthreception circuit 520 e. In other words, the sensor of the exampleincludes one transmission channel and four reception channel, andcombines and processes signals of four channels.

The transmitting/receiving unit of the sensor including the flat beamgenerating array antenna of the example can be applied to a sensor formeasuring a distance to an obstacle or the like, and a relative speed ofan obstacle or the like. Further, the flat beam generating array antennaof the invention can be applied to a sensor which measures an up-downposition (angle from a horizontal plane) of an obstacle or the like inthe up-down direction (direction of the first imaginary line A1-A1′) anda right-left position (angle from the front direction) of an obstacle orthe like in the right-left direction (direction of the sixth imaginaryline C2-C2′).

Example 11

FIG. 13 is a block diagram of an example of an in-vehicle systemincluding the sensor including the flat beam generating array antennaaccording to Example 11.

The in-vehicle system of Example 11 includes the flat beam generatingarray antennas of Example 1 to 4, the first transmission circuit 510 a,the first reception circuit 520 a, the second reception circuit 520 b,the fourth reception circuit 520 d, the fifth reception circuit 520 e,the signal processing circuit 700, and a vehicle control circuit 800.

The signal processing circuit 700 is connected to the first transmissioncircuit 510 a, the first reception circuit 520 a, the second receptioncircuit 520 b, the fourth reception circuit 520 d, and the fifthreception circuit 520 e. The signal processing circuit 700 supplies asignal to be transmitted from the antenna to the first transmissioncircuit 510 a, and processes the signals output from the first receptioncircuit 520 a, the second reception circuit 520 b, the fourth receptioncircuit 520 d, and the fifth reception circuit 520 e.

The vehicle control circuit 800 is connected to the signal processingcircuit 700. The connection between the vehicle control circuit 800 andthe signal processing circuit 700 may be wired by cable or wireless suchas wireless Local Access Network (LAN).

The vehicle control circuit 800 has a function of controlling theoperation of a moving body such as a power train control and a vehiclebody control according to the signal output from the signal processingcircuit 700.

The operation of the sensor including the flat beam generating arrayantenna of the example is the same as that of Example 10. The vehiclecontrol circuit 800 recognizes the position of an obstacle or the like,and the distance to an obstacle or the like by the signal output fromthe signal processing circuit 700 and outputs a control signal to apower train control unit or a vehicle body control unit, in such amanner that the movement of a moving body according to the surroundingsituation is controllable. Thus, the in-vehicle system of the examplefunctions as a driving support system.

Example 12

FIG. 14 is a diagram illustrating an attachment angle of the flat beamgenerating array antenna of Examples 9 and 10 described above. InExamples 12 and 13, variations of the attachment angle of the antennawill be described.

In Example 12, an antenna (radiation-side opening portion) is arrangedsuch that the first imaginary line A1-A1′, a fourth imaginary lineA2-A2′, and a fifth imaginary line A3-A3′ become the vertical directionand a seventh imaginary line E1-E1′ passing the center of the firstimaginary line A1-A1′, the center of the fourth imaginary line A2-A2′,and the center of the fifth imaginary line A3-A3′ becomes the horizontaldirection.

The vertical (direction along the first imaginary line A1-A1′, thefourth imaginary line A2-A2′, and the fifth imaginary line A3-A3′)length of the radiation-side opening portion of each antenna is widerthan the horizontal (direction along the seventh imaginary line E1-E1′)width thereof. Therefore, in the cross-sectional shape perpendicular tothe radiation direction of the beam radiated from the antenna of theexample, the direction in the vertical direction is narrow and thehorizontal direction is wide. With such an antenna structure, it ispossible to realize radar having a wide irradiation angle in thehorizontal direction while solving the problem of reducing the loadclutter noise.

The sensor including the antenna of Example 12 can be attached to eitherthe front side, the lateral side, or the rear side of a moving body.

Example 13

FIG. 15 is a view illustrating an attachment angle of the sensorincluding the flat beam generating array antenna of Example 9 and 10described above to a moving body. In Example 13, an example in which along side of an opening portion of the antenna is inclined from thevertical direction will be described.

In Example 13, as illustrated in FIG. 15, an antenna (radiation-sideopening portion) is arranged in a state where the first imaginary lineA1-A1′ and the seventh imaginary line E1-E1′ (horizontal direction) forma polarization angle 50 a. An angle formed by the fourth imaginary lineA2-A2′ and the seventh imaginary line E1-E1′ and an angle formed by thefifth imaginary line A3-A3′ and the seventh imaginary line E1-E1′ arealso the polarization angle 50 a. It is preferable that the polarizationangle 50 a is 45°. Since the beam radiated from the antenna of theExample 13 has a polarization angle of 45° with respect to the verticaldirection, the influence of the load clutter noise can be reduced.

Further, the sensor including the antenna of Example 13 can be attachedto either the front side, the lateral side, or the rear side of themoving body.

Hereinbefore, the preferred modes of the structure and the operation ofthe flat beam generating array antenna, the sensor including the flatbeam generating array antenna, and the in-vehicle system including thesensor of the invention are described using the Examples 1 to 13. Thenumber of radiating portions constituting the flat beam generating arrayantenna of the invention may be different from those of Examples 1 to 13and the effect of the flat beam generating array antenna of theinvention can be obtained. Furthermore, even when the shape of theradiating portion is different from those of Examples 1 to 13, when thelongitudinal direction of one radiation side opening portion is longerthan the transverse direction, the effect of the flat beam generatingarray antenna of the invention can be obtained.

Further, in Examples 1 to 13, the first to third dielectric lenses 300 ato 300 c have convex shapes bulging in the direction of the first to sixradiating portions 110 a to 110 f. However, the first to thirddielectric lenses 300 a to 300 c may have convex shapes bulging in anopposite direction from the first to sixth radiating portions 110 a to110 f. In addition, the shape of the first to third dielectric lenses300 a to 300 c is not a cylindrical shape but may be a convex surfacehaving a rotating dipole shape.

Further, the types and the number of combinations of the flat beamgenerating array antenna and the sensor including the flat beamgenerating array antenna may have arbitrary combinations other thanthose of the examples described above.

Further, the attachment angle of the sensor including the flat beamgenerating antenna to the moving body and the direction of the beamradiated from the flat beam generating antenna may have arbitrary formsother than those of Examples 12 and 13.

Also, the material constituting the dielectric substrate 100 may beeither a resin material, a ceramic material, or a semiconductormaterial.

As described above, according to the examples of the present invention,there are provided a plurality of radiating portions formed on asubstrate, and a plurality of dielectric lenses respectively convertingthe spherical wave radiated from each radiating portion into the planewave and the dielectric lens is formed in a shape where thecross-sectional surface perpendicular to the beam radiation directionhas a shape in which a beam having the second direction narrower thanthe first direction perpendicular to the second direction is radiated,and further a plurality of dielectric lenses are arranged side by sidein the second direction so that the beams radiated from the respectivedielectric lenses are synthesized. Thus, it is possible to reduce thesize of the dielectric lenses and shorten the focal length. Therefore,it is possible to reduce the size of the flat beam generating antenna.In particular, a length in a depth direction can be reduced.

In addition, the dielectric lens has a shape in which the seconddirection is longer than the first direction and the dielectric lens isinstalled so that the first direction becomes a horizontal direction andthe second direction becomes a vertical direction. Therefore, thedielectric lens can generate a flat beam with a wide horizontal width.

Furthermore, a plurality of waveguides (horns) propagating radio wavesradiated from the radiating portions are provided, and each dielectriclenses are installed in the radiation-side opening portions (openingportions on the opposite side to the radiating portions) of therespective waveguides. Therefore, the gain of the antenna can beimproved.

In addition, since the shape of the radiation-side opening portion ofthe waveguide includes at least four straight sides, it is possible toincrease the opening area and improve the gain of the antenna.

In addition, a reference potential portion formed around the radiatingportion on the substrate and serving as a reference potential of theradiating portion is provided and the reference potential portion iselectrically connected to the waveguide. Therefore, the reflection atthe entrance of the horn can be reduced, and thus the gain can beimproved by reducing the loss of the antenna.

Further, since the dielectric lens is formed in a convex shape having athick central portion and a thin peripheral portion, the gain of theantenna can be improved.

In addition, since the dielectric lens is a cylindrical lens having ahyperbolic shape in which the thickness in the first direction(horizontal direction) is constant and the center portion in the seconddirection (vertical direction) is thick, the gain of the antenna can beimproved. In particular, by using the horn and the cylindrical lenstogether, electromagnetic waves converted into plane waves by the hornwill enter the surface of the cylindrical lens, so that a flat beam withreduced beam disturbance can be generated.

In addition, since the plurality of radiating portions and the pluralityof dielectric lenses are arranged side by side in the up-down directionand the right-left direction, obstacles can be detected from thehorizontal direction and the vertical direction. For example, it ispossible to detect an uphill slope ahead and obstacles separately.

The invention is not limited to the examples described above andincludes various modification examples and equivalent structures withinthe scope of the appended claims. For example, the examples describedabove are described in detail in order to explain the invention in aneasy-to-understand manner and the invention is not necessarily limitedto those including all the configurations described. In addition, apartof the configuration of one example may be replaced by the configurationof another example. Further, the configuration of one embodiment may beadded to the configuration of another embodiment. In addition, otherconfigurations may be added, deleted, or replaced with respect to a partof the configuration of each example.

The configurations, functions, processing units, processing means, andthe like described above may be realized by hardware, for example, bydesigning a part or all of them with an integrated circuit or the like,or realized by software by a processor interpreting and executing aprogram realizing the respective functions.

Information such as programs, tables, files, and the like which realizethe respective functions can be stored in a storage device such as amemory, a hard disk, and a solid state drive (SSD), or a recordingmedium such as an IC card, an SD card, and a DVD.

Further, control lines and information lines which are considerednecessary for the explanation are illustrated and not all control linesand information lines necessary for mounting are illustrated. In fact,it can be thought that almost all configurations are interconnected.

1. An antenna comprising: a plurality of radiating portions which are formed on a substrate; and a plurality of dielectric lenses for respectively converting a spherical wave radiated from each radiating portion into a plane wave, wherein the shape of a cross section of each dielectric lens perpendicular to a radiation direction of a beam is formed in a shape which radiates a beam which is narrower in a second direction than in a first direction orthogonal to the second direction, and the plurality of dielectric lenses are arranged side by side in the second direction so that beams radiated from the respective dielectric lenses are synthesized.
 2. The antenna according to claim 1, wherein the dielectric lens has a shape which is longer in the second direction than in the first direction, and the dielectric lens is installed such that the first direction extends along a horizontal direction and the second direction extends along a vertical direction.
 3. The antenna according to claim 1, further comprising: a plurality of waveguides for propagating radio waves radiated from the radiating portions, wherein each dielectric lens is installed at an opening portion of each waveguide on an opposite side of the radiating portion.
 4. The antenna according to claim 3, wherein the shape of the opening portion of the waveguide on the opposite side of the radiating portion includes at least four or more straight sides.
 5. The antenna according to claim 3, further comprising: a reference potential portion which is formed around the radiating portion on the substrate and serves as a reference potential of the radiating portion, wherein the reference potential portion is electrically connected to the waveguide.
 6. The antenna according to claim 1, wherein the dielectric lens has a shape of a thick central portion and a thin peripheral portion in a direction in which the beam is radiated.
 7. The antenna according to claim 1, wherein the dielectric lens is a cylindrical lens having a hyperbolic shape in which the thickness in the first direction is constant and a central portion is thick in the second direction.
 8. The antenna according to claim 1, wherein the plurality of radiating portions and the plurality of dielectric lenses are arranged side by side in an up-down direction and a right-left direction.
 9. A sensor including the antenna according to claim 1, comprising: one or more transmission circuits connected to the radiating portions.
 10. A sensor including the antenna according to claim 1, comprising: one or more reception circuits connected to the radiating portions.
 11. A sensor including the antenna according to claim 1, comprising: transmission circuits; and reception circuits, wherein the transmission circuits are connected to one or more of the plurality of radiating portions, and the reception circuits are respectively connected to the radiating portions other than the radiating portions to which the transmission circuits are connected.
 12. The sensor according to claim 11, further comprising: a signal processing unit which is connected to the transmission circuits and the reception circuits.
 13. An in-vehicle system including the sensor according to claim 12, comprising: a vehicle control unit which is connected to the signal processing unit. 